5 Life on Earth Earth is the only planet in the Solar System with the conditions for life to exist. These conditions are: Liquid water is essential for all life on Earth. It covers more than 70 % of the Earth's surface. Most of it is salt water in the oceans. The distance from the Sun is just right for water to remain in a liquid state. The temperature is not too hot and not too cold. The atmosphere is the layer of gases that surrounds the Earth. It keeps the Earth's surface at a comfortable temperature. It contains the oxygen that we breathe. 8 ●○○ DESCRIBE. What are the Earth's movements? 9 ●○○ ANSWER in your notebook. What causes day and night? What causes the seasons? 10 ●○○ NAME the conditions that make life possible on the Earth. oBSERVE If you are in space over the North Pole, looking down at the Earth: In which direction is the planet spinning: clockwise or anticlockwise? B e a Sc i e nt i s t ! n i n e t y - t h r e e · 93
RkJQdWJsaXNoZXIy